From f61f1b5717dec9968efd6c8d61bd73b7a61b72a0 Mon Sep 17 00:00:00 2001 From: Suresh Siddha <suresh.b.siddha@intel.com> Date: Wed, 15 Oct 2008 07:46:27 -0700 Subject: [PATCH] x86: fix compat-vdso Jeff Chua reported that this patch: > -#define PTE_IDENT_ATTR 0x007 /* PRESENT+RW+USER */ > -#define PDE_IDENT_ATTR 0x067 /* PRESENT+RW+USER+DIRTY+ACCESSED */ > +#define PTE_IDENT_ATTR 0x003 /* PRESENT+RW */ > +#define PDE_IDENT_ATTR 0x063 /* PRESENT+RW+DIRTY+ACCESSED */ broke kernels with CONFIG_COMPAT_VDSO set with this init segfault: init[1]: segfault at ffffe01c up b7f0dc28 sp bfc26628 error 5 in ld-2.7.90.so[b7f0b000+1c000] Include USER bit in the PDE_IDENT_ATTR only, as the protection bits are combined from the PDE and PTE entries. This will allow the high mapped VDSO page in the case of CONFIG_COMPAT_VDSO to be user readable. Reported-by: Jeff Chua <jeff.chua.linux@gmail.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Tested-by: Jeff Chua <jeff.chua.linux@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> --- include/asm-x86/pgtable.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h index ed932453ef26a..e9f10af50f494 100644 --- a/include/asm-x86/pgtable.h +++ b/include/asm-x86/pgtable.h @@ -138,8 +138,13 @@ #ifdef CONFIG_X86_64 #define __PAGE_KERNEL_IDENT_LARGE_EXEC __PAGE_KERNEL_LARGE_EXEC #else +/* + * For PDE_IDENT_ATTR include USER bit. As the PDE and PTE protection + * bits are combined, this will alow user to access the high address mapped + * VDSO in the presence of CONFIG_COMPAT_VDSO + */ #define PTE_IDENT_ATTR 0x003 /* PRESENT+RW */ -#define PDE_IDENT_ATTR 0x063 /* PRESENT+RW+DIRTY+ACCESSED */ +#define PDE_IDENT_ATTR 0x067 /* PRESENT+RW+USER+DIRTY+ACCESSED */ #define PGD_IDENT_ATTR 0x001 /* PRESENT (no other attributes) */ #endif -- GitLab